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Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Dec 13, 2015

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Page 1: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.
Page 2: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Phylogeny of Arthropods

Arthropoda

Worm-likeAncestor

Trilobites(extinct)

Annelids(worms)

Onychophorans(worms w/legs)

Chelicerates(spiders)

Crustaceans(lobsters)

Insects(butterflies)

Page 3: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

General Characteristics

• metamerism (segmented body)

• jointed appendages

• bilateral symmetry

• secreted exoskeleton

• ecdysis (molting)

• open circulatory system

• ventral nerve cord and brain

                                                                                 

Page 4: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

DIVERSITY Numbers

• about 80% of all animals are arthropods • estimated to be over 30 million arthropods • far more of them than all other metazoan species

combined • in virtually every conceivable environment:

marine, terrestrial, freshwater, and aerial habitats.

Phylum ArthropodaSubphylum Trilobita (extinct)Subphylum ChelicerataSubphylum CrustaceaSubphylum Uniramia (insects)

Page 5: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Phylum ArthropodaSubphylum Trilobita (extinct)Subphylum ChelicerataSubphylum CrustaceaSubphylum Uniramia (insects)

Page 7: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Open Circulatory System

• Doral heart surrounded by pericardial sinus

• Blood (hemolymph) enters heart through ostia (openings) pumped through arteries

• Hemolymph- colorless; contains hemocyanin

• Hemocoel- blood cavity

Page 8: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Open Circulatory System

Page 9: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Compound Eye

Facet

LensCrystalline conePigment cells

Visual cells

Nerve fibers from visual cells

Optic nerveOmmatidia

Page 10: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

1. General • most arthropods are gonochoric • fertilization may be external or internal in

aquatic arthropods • always internal in terrestrial species

2. Sperm Transfer • sperm transfer usually by mating or

copulation • females usually store the sperm in a

seminal receptacle

REPRODUCTION

Page 13: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Subphylum Chelicerata • xiphosurans (horseshoe crabs),

arachnids, sea spiders • mostly terrestrial • cephalothorax-abdomen • 6 pairs cephalothoracic

appendages • chelicerae, pedipalps, 4 pairs legs • no antennae

Page 14: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

a. Xiphosura (horseshoe crab, Limulus polyphemus)

b. Arachnida •most chelicerates are arachnids •several taxa (orders), many are common and familiar

SCORPIONES (scorpions )ARANAE (spiders )OPILIONES (harvestmen, daddy longlegs )PSEUDOSCORPIONES (pseudoscorpions)ACARINI (mites and ticks )

c. Pycnogonida (the giant sea spider, Colossendeis australis)

Subphylum Chelicerata

                                                                

Page 15: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

• Limulus is a benthic scavenger and predator. • Prey include clams and other invertebrates that it digs for in

the sand.• The tail spine is used as a self-righting mechanism if the

animal is overturned accidentally. Lives up to 19 years• Reaches sexual maturity at about 9 to 12 years old

Horseshoe CrabLimulus polyphemus, Carcinoscorpius rotunda, and Tachypleus gigas.

Page 16: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

• Mates during spring and summer full and new moons, onto ocean beaches.

• Females lay up to 30 thousand eggs, which males fertilize before burying them in the sand

Horseshoe Crab

Page 19: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Arachnid

Page 20: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

• a heterogeneous taxon with many subtaxa

• two pairs antennae • marine, freshwater, and terrestrial • Primarily aquatic • Free-floating larval stage • 26,000+ known species

Subphylum Crustacea

Page 21: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

ANOSTRACA

• fairy shrimp and brine shrimp

PHYLLOPODA

• tadpole shrimps, ostracod, water fleas

MALACOSTRACA

• the largest, most heterogeneous, and diverse crustacean taxon

• shrimps, crabs, lobsters, mantis shrimps, pillbugs, crayfishes

COPEPODA

• copepods

• enormous ecological importance as planktonic herbivores

CIRRIPEDIA

• barnacles

Subphylum Crustacea

Page 22: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Arthropod Development

Zoea MegalopsNauplius

Page 23: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Gills a. General

• gills are evaginations • typical of aquatic animals • blood is oxygenated by gills • oxygen delivered to tissues by blood

b. Crustacean Gills • crustacean gills are usually associated with

appendages • blood circulates through the gill and is oxygenated

c. Book Lungs • present in many arachnid orders • similar to book gills of horseshoe crabs • oxygen transport from the lungs to the tissues is by

blood

Respiration

Page 24: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Subphylum Uniramia

Page 25: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.
Page 26: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Decorator Crab

Sponge crab

Camouflage

Page 27: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

Camouflage: anemone crab

Page 28: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

coral guard crabs and pocilloporid corals

coral guard crabs and pocilloporid corals

Page 29: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

gall crabs and pocilloporid corals

gall crabs and pocilloporid corals

Page 30: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

scarlet cleaner shrimp

scarlet cleaner shrimp

Page 31: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

sea cucumber crab and sea cucumberssea cucumber crab and sea cucumbers

Page 32: Phylogeny of Arthropods Arthropoda Worm-like Ancestor Trilobites (extinct) Annelids (worms) Onychophorans (worms w/legs) Chelicerates (spiders) Crustaceans.

pompom crabs and sea

anemones

pompom crabs and sea

anemones